On Tuesday (May 1), four years to the day after President Bush declared that "major combat operations in Iraq have ended," and that "in the battle of Iraq, the United States and our allies have prevailed," he vetoed a military-spending bill that would have called for U.S troop withdrawals beginning October 1, saying it was "a rigid and artificial deadline."

"All the terrorists would have to do is mark their calendars and gather their strength," the president said in a press conference at the White House. "I believe [this bill] would demoralize the Iraqi people and send a signal that America would not honor its commitments."

Passed last week by both houses of Congress — and signed and sent to Bush Tuesday — the $124.2 billion supplemental bill was the first major salvo from a newly elected Democratic majority (see "It's Official: Democrats Take Over Both Houses Of Congress") to end American involvement in the increasingly unpopular Iraq war.

While the bill would fund military conflicts in both Iraq and Afghanistan, it also called for American troop withdrawal from Iraq beginning in October, with an eye toward removing all of the nearly 150,000 U.S. combat troops by March 2008.

The president, meanwhile, said that a timetable would only be a "deadline for failure."

"It makes no sense to tell the enemy when you plan to start withdrawing," he said. "[This bill] would deny our brave men and women in uniform the flexibility they [need]."

Both the bill and the veto are part of a high-stakes, checks-and-balances game of political chicken. Congress, which has the power to fund wars, cannot remove troops on its own. The president, who can remove soldiers, needs Congress to make financial appropriations.

Bush's veto is only his second since taking office. Congress can override a presidential veto and push a bill into law with a super-majority, or two-thirds majority, in both houses, but any move to do so on this bill would almost certainly fail, since the legislation passed by only a slim margin last week. The 51-46 Senate vote fell largely along party lines.

That means lawmakers in Congress might have to go back to the drawing board to draft new legislation that will effectively remove all language related to troop withdrawal. One possible compromise is for Congress to replace troop withdrawal with a series of goals, or benchmarks, for the newly installed Iraqi government.

Earlier Tuesday, Bush invited top lawmakers to the White House on Wednesday to discuss these and other compromises.

"I'm confident that with good will on both sides, we can agree on a bill that would get our troops the money and flexibility they [need]," the president concluded.